Halloran Landon J S, Millwater Jeremy, Hunkeler Daniel, Arnoux Marie
Centre d'hydrogéologie et de géothermie (CHYN), Université de Neuchâtel, rue Émile-Argand 11, 2000 Neuchâtel, Switzerland.
Centre d'hydrogéologie et de géothermie (CHYN), Université de Neuchâtel, rue Émile-Argand 11, 2000 Neuchâtel, Switzerland; Now at: CSD Ingenieure AG, Schachenallee 29A, 5000 Aarau, Switzerland.
Sci Total Environ. 2023 Dec 1;902:166009. doi: 10.1016/j.scitotenv.2023.166009. Epub 2023 Aug 2.
Climate change will have-and, in much of the world, is already having-a pronounced impact on alpine water resources. A deeper understanding of the future role of groundwater in alpine catchments, including quantification of climate change impacts on groundwater discharge, is vital for understanding the future of alpine water resources as a whole. Here, we develop and couple a geophysics-informed groundwater model with a net recharge model to investigate the impacts of climate change on a nival-regime alpine headwater catchment with significant unconfined Quaternary aquifer coverage. Flow in the groundwater-fed stream at the catchment outlet is analysed to determine changes in its annual dynamics. Comparing the periods 2020-2040 and 2080-2100 under ten RCP-8.5 climate models, we find a 35 % decrease in mean groundwater discharge and an increase in no-flow periods from ~0 % to 4.3 %. We also observe significant changes to the timing of monthly mean discharge maxima and minima, which shift ~1 month and ~5 months earlier, respectively. While groundwater has the potential to dampen the impacts of snow cover loss, currently perennial nival-regime alpine streams could be at risk of becoming intermittent by the end of the century. Our study underscores the increasingly critical role that groundwater will play in alpine catchments and emphasizes the need for quantitative understanding of the limits to its buffering capacity.
气候变化已经且在世界许多地区正在对高山水资源产生显著影响。更深入地了解地下水在高山集水区未来所起的作用，包括量化气候变化对地下水排放的影响，对于全面理解高山水资源的未来至关重要。在此，我们开发了一个基于地球物理学的地下水模型并将其与净补给模型相结合，以研究气候变化对一个具有大面积无压第四纪含水层覆盖的雪水补给型高山源头集水区的影响。分析集水区出口处由地下水补给的溪流中的水流，以确定其年度动态变化。在十个RCP - 8.5气候模型下比较2020 - 2040年和2080 - 2100年这两个时期，我们发现平均地下水排放量减少了35%，无流期从约0%增加到4.3%。我们还观察到月平均流量最大值和最小值出现时间的显著变化，分别提前了约1个月和约5个月。虽然地下水有可能减轻积雪损失的影响，但到本世纪末，目前常年处于雪水补给状态的高山溪流可能面临变为间歇性溪流的风险。我们的研究强调了地下水在高山集水区将发挥的日益关键的作用，并强调需要定量了解其缓冲能力的限度。
